Re: [PATCH 2/2] util: add util function buffer_zero_avx512()

[Paolo Bonzini]

On 13/02/20 08:52, Robert Hoo wrote:
> +
> +}
> +#pragma GCC pop_options
> +#endif
> +
> +
>  /* Note that for test_buffer_is_zero_next_accel, the most preferred
>   * ISA must have the least significant bit.
>   */
> -#define CACHE_AVX2    1
> -#define CACHE_SSE4    2
> -#define CACHE_SSE2    4
> +#define CACHE_AVX512F 1
> +#define CACHE_AVX2    2
> +#define CACHE_SSE4    4
> +#define CACHE_SSE2    6

This should be 8, not 6.

Paolo

>  
>  /* Make sure that these variables are appropriately initialized when
>   * SSE2 is enabled on the compiler command-line, but the compiler is
> @@ -226,6 +268,11 @@ static void init_accel(unsigned cache)
>          fn = buffer_zero_avx2;
>      }
>  #endif
> +#ifdef CONFIG_AVX512F_OPT
> +    if (cache & CACHE_AVX512F) {
> +        fn = buffer_zero_avx512;
> +    }
> +#endif
>      buffer_accel = fn;
>  }
>  
> @@ -255,6 +302,9 @@ static void __attribute__((constructor)) 
> init_cpuid_cache(void)
>              if ((bv & 6) == 6 && (b & bit_AVX2)) {
>                  cache |= CACHE_AVX2;
>              }
> +            if ((bv & 6) == 6 && (b & bit_AVX512F)) {
> +                cache |= CACHE_AVX512F;
> +            }
>          }